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Abstract : ObjectiveThe purpose of this study was to evaluate the effects of three different surface conditioning methods on the shear bond strength (SBS) of metal brackets bonded directly to gold alloy with chemically cured resin.MethodsTwo hundred ten type III gold alloy specimens were randomly divided into six groups according to the combination of three different surface conditioning methods (aluminum oxide sandblasting only, application of a metal primer after aluminum oxide sandblasting, silica coating and silanation) and thermocycling (with thermocycling, without thermocycling). After performing surface conditioning of specimens in accordance with each experimental condition, metal brackets were bonded to all specimens using a chemically cured resin. The SBS was measured at the moment of bracket debonding, and the resin remnants on the specimen surface were evaluated using the adhesive remnant index.ResultsApplication of metal primer after aluminum oxide sandblasting yielded a higher bond strength than that with aluminum oxide sandblasting alone (p < 0.001), and silica coating and silanation yielded a higher bond strength than that with metal primer after aluminum oxide sandblasting (p < 0.001). There was no significant change in SBS after thermocycling in all groups.ConclusionsWith silica coating and silanation, clinically satisfactory bond strength can be attained when metal brackets are directly bonded to gold alloys using a chemically cured resin.
Abstract : ObjectiveThe purpose of this in vitro study was to examine the effects of fluoridated, casein phosphopeptide.amorphous calcium phosphate complex (CPP-ACP)-containing, and functionalized β-tricalcium phosphate (fTCP)-containing toothpastes on remineralization of white spot lesions (WSLs) by using Quantitative light-induced fluorescence (QLF-D) Biluminator™ 2.MethodsForty-eight premolars, extracted for orthodontic reasons from 12 patients, with artificially induced WSLs were randomly and equally assigned to four treatment groups: fluoride (1,000 ppm), CPP-ACP, fTCP (with sodium fluoride), and control (deionized water) groups. Specimens were treated twice daily for 2 weeks and stored in saliva solution (1:1 mixture of artificial and human stimulated saliva) otherwise. QLF-D Biluminator™ 2 was used to measure changes in fluorescence, indicating alterations in the mineral contents of the WSLs, immediately before and after the 2 weeks of treatment.ResultsFluorescence greatly increased in the fTCP and CPP-ACP groups compared with the fluoride and control groups, which did not show significant differences.ConclusionsfTCP- and CPP-ACP-containing toothpastes seem to be more effective in reducing WSLs than 1,000-ppm fluoride-containing toothpastes.
Abstract : ObjectiveTo evaluate the long-term effects of self-ligating brackets (SLBs) on transverse dimensions of arches and skeletal and soft tissues and to quantitatively evaluate the treatment outcome after non-extraction treatment with SLBs.MethodsThe sample consisted of 24 (18 female and six male) subjects, with a mean age of 14.23 ± 2.19 years, who received treatment with the Damon®3 appliances. Complete records including cephalometric radiographs and plaster models were obtained before treatment (T1), immediately after treatment (T2), six months after treatment (T3), and two years (T4) after treatment. Digital study models were generated. Twenty lateral cephalometric, six frontal cephalometric, and eight dental cast measurements were examined. The Peer Assessment Rating index was used to measure the treatment outcome. The Wilcoxon test was applied for statistical analysis of the changes.ResultsThere were significant increases in all transverse dental cast measurements with active treatment. There was some significant relapse in the long term, particularly in maxillary width (p < 0.05). Statistically significant increases were found in nasal (p < 0.001), maxillary base, upper molar, lower intercanine, and antigonial (p < 0.05) widths in T1-T2. Lower incisors were proclined and protruded in T1-T2.ConclusionsSLBs correct crowding by mechanisms involving incisor proclination and protrusion and expansion of the dental arches, without induction of clinically significant changes in hard and soft tissues of the face.
Abstract : ObjectiveThis study evaluated the cytotoxicity and genotoxicity of fixed orthodontic treatment with three different light-cured orthodontic bonding composites by analyzing micronucleus (MN) formation in the buccal mucosa during a 6-month period.MethodsThirty healthy volunteers were selected from consecutive patients referred for orthodontic treatment. Equilibrium 2 brackets and molar tubes (Dentaurum) were bonded with three different light-cured orthodontic bonding composites-Transbond XT (3M Unitek), Kurasper F (Kuraray Europe), or GrenGloo (Ormco Corporation)- to all teeth in both arches. Exfoliated buccal epithelial cells were scraped from the middle part of the inner cheeks with sterile cement spatulas before treatment and at 1, 3, and 6 months after treatment. MNs and nuclear alterations, such as karyorrhexis (KR), karyolysis (KL), and binucleated cells (BNs), were scored under a light microscope. Repeated measure ANOVA was used to calculate statistical differences in degenerative nuclear abnormalities.ResultsMN rates did not significantly differ among different time points within the same cell type (p > 0.05). In contrast, the number of BNs in buccal epithelial cells significantly increased in all composite groups (p < 0.01, Transbond XT; p < 0.001, Kurasper F and GrenGloo). KL frequency significantly increased between the beginning and end of the study in the Kurasfer F (0.80 ± 0.79 to 1.90 ± 1.10; p < 0.05) and GrenGloo (1.30 ± 1.06 to 2.40 ± 1.08; p < 0.05) groups.ConclusionsAfter 6 months of fixed orthodontic treatment with different light-cured composites, morphological signs of cytotoxicity were observed but genotoxic effects were absent.
Abstract : ObjectiveTo evaluate the active-treatment effects of the Forsus fatigue resistant device (Forsus) during comprehensive correction of Class II malocclusion in growing patients.MethodsFifty-four patients (mean age, 12.5 ± 1.2 years) with Class II division 1 malocclusion were consecutively treated with fixed app-liances in combination with Forsus. Lateral cephalograms were analyzed at the beginning of the fixed treatment (T1), Forsus insertion (T2), its removal (T3), and end of the comprehensive therapy (T4). Statistical comparisons were carried out by repeated-measures ANOVA with Tukey's post-hoc test (p < 0.05).ResultsThe overall therapeutic effects were mainly dentoalveolar and occurred mostly during the active treatment with Forsus (T2-T3, mean duration = 0.5 ± 0.1 years). The overjet and overbite decreased significantly (-3.5 and -1.5 mm, respectively) and the molar relationship improved by 4.3 mm. These changes were associated with significant retroclination of the maxillary incisors (-3.1°), proclination and intrusion of the mandibular incisors (+5.0° and -1.5 mm, respectively), and mesialization of the mandibular molars (+2.0 mm).ConclusionsForsus had mainly dentoalveolar effects and contributed largely to the overall therapeutic outcome.
Abstract : An 8-years old boy with facial asymmetry and unilateral posterior crossbite on the left side received orthopedic and orthodontic treatment. During the first phase of treatment, the narrow maxillary arch was expanded using an acrylic plate. Then, the acrylic plate was used as a bite block with occlusal indentations from the construction bite that was obtained with the incisors in a coincident dental midline. After the position of the mandible was stabilized, the second phase of orthodontic treatment was initiated using fixed appliances for detailing of the occlusion. Skeletal symmetry, ideal occlusion, and coincident dental midlines were thus achieved. Functionally, occlusal force balance and masticatory muscle activity were improved, and the chewing patterns were normalized.
2.6
2023 IF
